Use a subprocess wrapper that will throw if a command returns a non-zero result code

autotest.py

Index: autotest.py
===================================================================
--- a/autotest.py
+++ b/autotest.py
@@ -1,16 +1,16 @@
 #!/usr/bin/env python
 # coding: utf-8
 
 # This Source Code is subject to the terms of the Mozilla Public License
 # version 2.0 (the "License"). You can obtain a copy of the License at
 # http://mozilla.org/MPL/2.0/.
 
-import sys, os, subprocess, re, difflib, utils
+import sys, os, re, difflib, utils
 
 def run_tests():
   application = utils.ensureJSShell()
   env = {
     'LD_LIBRARY_PATH': os.path.relpath(os.path.dirname(application)),
   }
 
   baseDir = os.path.dirname(utils.__file__)
@@ -30,17 +30,17 @@ def run_tests():
       elif match and match.group(1).lower() == 'arguments':
         arguments = match.group(2).split(' ')
     handle.close()
 
     if arguments == None:
       continue
 
     command = [application, os.path.join(baseDir, 'jshydra.js'), file] + arguments
-    out = subprocess.Popen(command, stdout=subprocess.PIPE, stderr=subprocess.STDOUT, env=env).communicate()[0].replace('\r', '')
+    out = utils.run(command, utils.STREAMS_STDOUT, env=env).replace('\r', '')
     expected = open(file + '.expected', 'r').read().replace('\r', '')
     if out == expected:
       print '%s passed' % name
     else:
       print '%s failed! Log:' % name
       for line in difflib.unified_diff(expected.split('\n'), out.split('\n'), fromfile=file + '.expected', tofile=file + '.output'):
         print line
       print